{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40237", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.181Z", "datePublished": "2025-12-04T15:31:27.325Z", "dateUpdated": "2026-05-23T16:01:45.934Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-23T16:01:45.934Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/notify: call exportfs_encode_fid with s_umount\n\nCalling intotify_show_fdinfo() on fd watching an overlayfs inode, while\nthe overlayfs is being unmounted, can lead to dereferencing NULL ptr.\n\nThis issue was found by syzkaller.\n\nRace Condition Diagram:\n\nThread 1 Thread 2\n-------- --------\n\ngeneric_shutdown_super()\n shrink_dcache_for_umount\n sb->s_root = NULL\n\n |\n | vfs_read()\n | inotify_fdinfo()\n | * inode get from mark *\n | show_mark_fhandle(m, inode)\n | exportfs_encode_fid(inode, ..)\n | ovl_encode_fh(inode, ..)\n | ovl_check_encode_origin(inode)\n | * deref i_sb->s_root *\n |\n |\n v\n fsnotify_sb_delete(sb)\n\nWhich then leads to:\n\n[ 32.133461] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI\n[ 32.134438] KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]\n[ 32.135032] CPU: 1 UID: 0 PID: 4468 Comm: systemd-coredum Not tainted 6.17.0-rc6 #22 PREEMPT(none)\n\n\n\n[ 32.143353] Call Trace:\n[ 32.143732] ovl_encode_fh+0xd5/0x170\n[ 32.144031] exportfs_encode_inode_fh+0x12f/0x300\n[ 32.144425] show_mark_fhandle+0xbe/0x1f0\n[ 32.145805] inotify_fdinfo+0x226/0x2d0\n[ 32.146442] inotify_show_fdinfo+0x1c5/0x350\n[ 32.147168] seq_show+0x530/0x6f0\n[ 32.147449] seq_read_iter+0x503/0x12a0\n[ 32.148419] seq_read+0x31f/0x410\n[ 32.150714] vfs_read+0x1f0/0x9e0\n[ 32.152297] ksys_read+0x125/0x240\n\nIOW ovl_check_encode_origin derefs inode->i_sb->s_root, after it was set\nto NULL in the unmount path.\n\nFix it by protecting calling exportfs_encode_fid() from\nshow_mark_fhandle() with s_umount lock.\n\nThis form of fix was suggested by Amir in [1].\n\n[1]: https://lore.kernel.org/all/CAOQ4uxhbDwhb+2Brs1UdkoF0a3NSdBAOQPNfEHjahrgoKJpLEw@mail.gmail.com/" } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/notify/fdinfo.c" ], "versions": [ { "version": "a1a541fbfa7e97c1100144db34b57553d7164ce5", "lessThan": "950b604384fd75d62e860bec7135b2b62eb4d508", "status": "affected", "versionType": "git" }, { "version": "f0c0ac84de17c37e6e84da65fb920f91dada55ad", "lessThan": "bc1c6b803e14ea2b8f7e33b7164013f666ceb656", "status": "affected", "versionType": "git" }, { "version": "3c7c90274ae339e1ad443c9be1c67a20b80b9c76", "lessThan": "3f307a9f7a7a2822e38ac451b73e2244e7279496", "status": "affected", "versionType": "git" }, { "version": "c45beebfde34aa71afbc48b2c54cdda623515037", "lessThan": "d1894bc542becb0fda61e7e513b09523cab44030", "status": "affected", "versionType": "git" }, { "version": "c45beebfde34aa71afbc48b2c54cdda623515037", "lessThan": "a7c4bb43bfdc2b9f06ee9d036028ed13a83df42a", "status": "affected", "versionType": "git" }, { "version": "6.6.72", "lessThan": "6.6.73", "status": "affected", "versionType": "semver" }, { "version": "6.6.74", "lessThan": "6.6.115", "status": "affected", "versionType": "semver" }, { "version": "6.12.10", "lessThan": "6.12.56", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/notify/fdinfo.c" ], "versions": [ { "version": "6.13", "status": "affected" }, { "version": "0", "lessThan": "6.13", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.73", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.115", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.56", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.6", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6.72", "versionEndExcluding": "6.6.73" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6.74", "versionEndExcluding": "6.6.115" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.10", "versionEndExcluding": "6.12.56" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.17.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/950b604384fd75d62e860bec7135b2b62eb4d508" }, { "url": "https://git.kernel.org/stable/c/bc1c6b803e14ea2b8f7e33b7164013f666ceb656" }, { "url": "https://git.kernel.org/stable/c/3f307a9f7a7a2822e38ac451b73e2244e7279496" }, { "url": "https://git.kernel.org/stable/c/d1894bc542becb0fda61e7e513b09523cab44030" }, { "url": "https://git.kernel.org/stable/c/a7c4bb43bfdc2b9f06ee9d036028ed13a83df42a" } ], "title": "fs/notify: call exportfs_encode_fid with s_umount", 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